Preparation of Carbon Nanotube Coated Li₄Ti₅O₁₂ Nanosheets Heterostructure as Ultrastable Anodes for Lithium-Ion Batteries

Hierarchical ultrathin lithium titanate (LTO) nanosheets were in situ synthesized inside the carbon nanotubes via a precursor-morphology-controlled conversion strategy, which achieves good rate capacity and cycling stability, since it possesses more lithium-insertion channels and good electronic conductivity simultaneously. The as-prepared CNT@LTO materials exhibit a high specific capacity of 172.5 mA h g –1 at 10 C and long cycling stability with only 0.014% capacity loss per cycle. Ex situ electron energy loss spectroscopy (EELS) analysis of CNT@LTO materials at three different stages verifies that during the charge–discharge process only a fraction of the Ti 4+ species are reduced to Ti 3+ and the specific electrode reaction of spinel LTO occurs from spinel phase to rock-salt phase. Compared with pure LTO, CNT@LTO exhibits a more stable cycle performance and better electronic conductivity, which demonstrate that the CNTs not only provide good conductivity but also maintain structural stability.